The Three Lions boss swapped from the 4-2-3-1 that he used in World Cup qualifying to a 3-4-1-2 formation with Ruben Loftus-Cheek in an advanced midfield position as one of three starting debutants.
While seven injuries ruined his hopes of fielding a full-strength eleven to try and truly judge England's progress, a makeshift and inexperienced team coped well against the challenge of the 2014 World Cup champions.
Hailing his team's performance, Southgate said after: "I thought there were a few shaky moments in the first half, mainly due to Phil [Jones] carrying something, which opened up the opportunity once or twice.
"He seems fine, we've checked him out and it's something he's been carrying but it doesn't seem to be any worse so I think he'll be fine. From there really, it was an interesting game.
"Their system caused us some problems with [Mesut] Özil and [Leroy] Sané dropping in deeper and our system caused them problems with our No.8s in behind their midfield.
"It was a bit end-to-end but I thought we showed real composure with the ball throughout the team. Second half I thought we were tactically a bit better without the ball, we didn't concede too many chances.
"Maybe they have another level to go to but everyone knows what we're missing as well. Individually, some really top debuts and some really encouraging performances."
England boss happy with senior team's tactical development
While England allowed the visitors chances in the first-half, Jordan Pickford required to produce a sublime debut display to keep Timo Werner at bay at Wembley Stadium, they controlled proceedings in the second half and had chances to win the game.
On what he felt his side gained from playing in a different shape, Southgate said: "Against the better teams that we've played in the qualification games, tactically you've got very few questions to answer and the same problem to solve.
"I haven't liked us in a 4-3-2-1, our positioning and discipline with the ball has not been good. Tonight we had to be tactically right with and without the ball, that's the nature of the top games.
"The players have taken those concepts on really well, they're a bright group, they get it. But also we're asking them not just to go and play but to think about what they're doing all the time, where do they need to press, how do they press, not just blindly going and chasing around the field and playing with their hearts.
"We've got to be a team that are switched on because against the very best, if you get the pressing wrong then they'll carve you apart and that's happened a couple of times tonight.
"I think that's one of the most pleasing things of working with this group over a period of time, they're responding to that and I think they have experienced some of that with their clubs as well.
"It was a really young team in the end, by the time we've made the changes, with five debutants today, but they really took those things on board well."
Loftus-Cheek was named Man of the Match for a fine display in a No.10 role, the 21-year-old undoubtedly England's most creative influence with his surging runs from deep and inventive passing.
"I think a slightly different system opens up different possibilities because in the position that Ruben played tonight, you could play Dele [Alli] there or you could play [Adam] Lallana there; that different sort of profile of midfield player with a deeper one behind," Southgate said.
"I think we need the stability of the three behind that at the moment but also all of our guys at the back used the ball well. At times it was difficult for Germany to press us because of the composure we showed and the system we played.
"I think it was a brilliant experience for our players and we know have to to see if we can try and replicate that on Tuesday against opposition that rested a few of their players today. For me, it was a real positive tonight."
Southgate insists there is "loads" England can continue to improve on
The atmosphere was notably louder inside Wembley than in recent games where it had been subdued and frustrated by the performances of the England players.
But they played with more freedom and fluidity here and were far more entertaining than they have been of late.
"That is what we want to do," Southgate added. "The nature of the fixtures plays a part in that; it's a proper game tonight, top players that you're playing against, you've got to be switched on, a team that are going to come at you. It's a better spectacle for the crowd.
"The qualifying matches, it's the case of when you can score and how many you can score and we haven't been able to crack that nut quickly enough in games.
"Germany, every video I looked at, they were a goal ahead after 10 minutes in their qualifiers and that's where they're ahead of us in their evolution as a team.
"But in the games where we've had to play against the top teams, the atmospheres have been good.
"Tactically, the players have performed well. There's still loads we can get better at and the more we play that system, the better we'll get.
"I think the whole thing is better for the fans and also I think they'll have been encouraged by some new players that maybe they haven't seen before. There was a freshness and an energy about it."